Hi! I have a CM-126-ESS (Ethernet Smooth Stepper attached to a breakout board) that I purchased on Ebay, see attached photo. I have an ohmic tip on my plasma table to probe the top of the plate. I ran a wire from the ESS ground to the table frame, and another wire from an open input to the ohmic tip. This works great except about every 2 hrs. of operation the input pin quits working. I just move the wire to another pin and reassign it in Mach3 and its good to go for a couple more hrs. As far as I know all the inputs are optoisolated, but is there another way to wire ohmic probing? Maybe use a relay? I don't know what else could be doing it. I tried backing up to some of the former pins that had quit a few weeks ago and they still don't work. Any body else using this setup for plasma? Thanks for any input!  Brian

If I were building a plasma table from scratch, what is the proper way to set up the probe to reference the torch off of the top of the plate? Using a ohmic tip? I was reading posts on grounding and interference, and I figured out that 0V DC should not be connected to Earth/frame ground. So how do I get continuity for my ohmic tip to work if I can't connect to the frame of the table at all? I would like any input?!!

Am I the only one in the CNC plasma league? Anybody else using a Ethernet Smooth stepper for plasma?

Hi BLM,

Just my opinion...

The genuine USB Smooth Stepper is manufactured by Warp9 - what you have is a Chinese imitation which, I am led to believe, is inferior in many respects and this may be the root cause of your problem.
It appears you have destroyed some of the inputs so I think you should consider a new board is necessary and perhaps also consider using additional opto-isolators for your inputs in order to protect a new board from similar damage.
It may be a voltage spike type of problem in which case check all your wiring, earthing and grounding in particular the way in which you have earthed the various components of the whole system - ideally a single point earth (star), avoiding any earth loops would be preferable and treat earth and signal GND as two separate circuits.

Hope this helps.

Tweakie.

Hey thanks for the reply! This is a genuine ethernet smooth stepper mounted on an expensive Korean built BoB. One of my questions was, how can I use continuity probing without connecting signal ground to the frame/star ground? If not then what other way is there to probe top of plate with plasma?

See reply at Warp9 web site

Cheers
Roger